配置container-executor.cfg
vim etc/hadoop/container-executor.cfg yarn.nodemanager.linux-container-executor.group=yarn banned.users=root min.user.id=1000 allowed.system.users=yarn
注意：这个配置文件是通过C语言解析的，编码格式等很敏感。曾踩在坑里很久才出来。提示“yarn.nodemanager.linux-container-executor.group”配置找不到。
Caused by: ExitCodeException exitCode=24: Can't get configured value for yarn.nodemanager.linux-container-executor.group.
配置文件是否正确、和权限是否正确，可通过 ./bin/container-executor --checksetup 检查。
配置文件权限：（权限很重要，必须的步骤）
chown root:yarn bin/container-executor chmod 6050 bin/container-executor
配置yarn-site.xml
<!-- cgroup start -->
<property>
<name>yarn.nodemanager.container-executor.class</name>
<value>org.apache.hadoop.yarn.server.nodemanager.LinuxContainerExecutor</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.resources-handler.class</name>
<value>org.apache.hadoop.yarn.server.nodemanager.util.CgroupsLCEResourcesHandler</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.cgroups.hierarchy</name>
<value>/hadoop-yarn</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.cgroups.mount</name>
<value>true</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.cgroups.mount-path</name>
<value>/cgroup</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.group</name>
<value>yarn</value>
</property>
<property>
<name>yarn.nodemanager.resource.percentage-physical-cpu-limit</name>
<value>90</value>
</property>
<property>
<name>yarn.nodemanager.linux-container-executor.cgroups.strict-resource-usage</name>
<value>true</value>
</property>
<!-- cgroup end -->
启动cgroup服务：
service cgconfig start
启动后在/cgroup/下多出一堆文件：
root@hadoop3 hadoop-2.7.3]# ll /cgroup/ total 0 drwxr-xr-x 2 root root 0 Sep 22 12:27 blkio drwxr-xr-x 3 root root 0 Sep 22 12:27 cpu drwxr-xr-x 2 root root 0 Sep 22 12:27 cpuacct drwxr-xr-x 2 root root 0 Sep 22 12:27 cpuset drwxr-xr-x 2 root root 0 Sep 22 12:27 devices drwxr-xr-x 2 root root 0 Sep 22 12:27 freezer drwxr-xr-x 2 root root 0 Sep 22 12:27 memory drwxr-xr-x 2 root root 0 Sep 22 12:27 net_cls
还需要建立hadoop-yarn文件夹：（官方文档是说能自动建立，实际没有，可能是centos 6 和centos7区别的原因）
mkdir -p /cgroup/cpu/hadoop-yarn
如不建立可能会报如下错误：
org.apache.hadoop.yarn.server.nodemanager.LinuxContainerExecutor: Exit code from container executor initialization is : 22 ExitCodeException exitCode=22: Invalid permissions on container-executor binary. Caused by: java.io.IOException: Linux container executor not configured properly (error=22)
./sbin/yarn-daemon.sh start nodemanager
done!